Hello. I have a question. When Windows blends a .rar with a .jpg, how is the image changed? Ergo, what is process that allows such operation? I am asking because I am interested in replicating such a feat with a program of my own.

Your not really changing the image, your just hiding your secret data in the image data. Basically what is happening is the data your wanting to hide is being hidden in the least significant bit of the image data. To the windows program that is just viewing the image, the hidden data will be background noise that has no effect on how a windows program converts or interprets the image itself.

VPR3 wrote:Your not really changing the image, your just hiding your secret data in the image data. Basically what is happening is the data your wanting to hide is being hidden in the least significant bit of the image data. To the windows program that is just viewing the image, the hidden data will be background noise that has no effect on how a windows program converts or interprets the image itself.

That's one way to implement steganography, but the technique you're describing isn't used in this case. This is much more simpler technique.

This just seems to be appending the compressed(doesn't have to be compressed) file after the image.